Microtiter plates are used in many chemical, biochemical and biological processes ranging from simple chemical reactions and/or compound synthesis to analytical testing. Microtiter plates can come in various shapes, sizes and configurations. In certain instances the configuration of commercially available microtiter plates has undergone standardization. For example, the Society for Biomolecular Screening (SBS) has published recommended microtiter plate specifications for a variety of plate formats. These published standards set forth, inter alia, various requirements for length, width, depth, well geometry, well spacing, and form factor. Microtiter plates manufactured in accordance with these standards are assured to have certain dimensions and physical characteristics that allow users to design instruments, tests and procedures that can reliably use such standardized microtiter plates. Industry standards such as those published by the SBS ensure interchangeability and compatibility and allow automated handling. Recently, commercial manufacturers of equipment for processing and analyzing samples in multi-well plates have begun selling equipment that is capable of handling more than one plate type. It is readily understood that many of these instruments need to adjust their operation depending on the type of plate being handled.
Co-pending and commonly assigned U.S. pat. appln. Ser. No. 60/301,932, incorporated herein by reference in its entirety, discloses specialized microtiter plates that, preferably, adhere to the physical specifications of certain SBS standards. These specialized plates are, preferably, capable of being used with any automated plate handling system that adheres to the same SBS standards.
In preferred embodiments of the Ser. No. 60/301,932 application, specialized plates are disclosed that are suitable for use in specialized electrochemiluminescence-based assays and instruments. These specialized plates can be configured in many different ways, differing in the number of wells (96, 384, 1536 etc.), in the height of the well/plate (standard or deep-well), or in the well bottom shape (flat, round, conical, etc.). A further physical difference in the configuration of these specialized plates relates to the plate bottoms. The plate bottoms differ from standardized assay plates in that there may be patterns of electrodes on these plate bottoms. The electrodes may typically be arranged on the plate bottom such that each electrode may span one or more wells and/or such that each well spans one or more electrodes. These electrodes may be used for inducing electrochemiluminescence (ECL) reactions within the well that are designed to measure a particular analyte of interest. ECL is induced by stimulating, i.e., supplying electrical energy to, one or more electrodes within a well. Still further, some of these specialized plates incorporate binding reagents immobilized on the working electrodes found in the wells. Each well can contain a number of these binding reagents, referred to as spots or binding domains, in a number of different arrangements, or layouts. A single well containing a number of these distinct binding domains, or spots, is capable of testing a single sample for a number of different analytes of interest (typically, one analyte for each spot).
In certain instances, these specialized plates use groupings, or regions referred to as sectors, of electrodes located on the plate bottoms to simultaneously induce electrochemiluminescence in the wells having the grouped electrodes. Such sectors may be the result of physical groupings, (e.g., a group of electrodes that are electrically connected through leads on the plate bottom) or may be the result of the instrument stimulating more than one physically distinct electrode simultaneously. In any case, the number and layout of sectors across a plate can depend on the type of instrument to be used to process the plate. For example, one instrument could process a 96-well plate by stimulating a single column of the plate; i.e., a column of 8 wells at a time. In this instance, the plate could be divided into 12 sectors, each sector containing 8 wells. Yet another instrument may use a 2×3 grid of sectors partitioning a 96 well plate into 6 sectors of 16 wells each. Still yet another instrument could have multiple sectors inside each well wherein each sector represents an individually addressable electrode. In this instance the individual addressable electrode may also define a binding domain or spot. As is described in more detail in the Ser. No. 06/301,932 application, the grouping of electrodes and/or wells into sectors provides certain advantages in the analysis of luminescence emitted from a plate when compared to the simultaneous measurement of luminescence from whole plates or the serial detection of luminescence from each individual well. U.S. Pat. No. 6,200,531 (hereby incorporated by reference) discloses instruments that use fluidics to move samples from a plate to be assayed into a separate vessel or chamber where the analysis takes place. In such a fluidics-based instrument, a hollow probe or pipette that is lowered into the well may be used to aspirate the sample and transfer it into the special vessel or chamber for testing. It is readily apparent then that the dimensions and configuration of the plate will determine the probe depth and motion profiles. Past attempts at enabling instruments to process various plate types and/or various plate configurations coded the instrument control software with all of the requisite information for each anticipated plate type. However, such an approach requires that all anticipated plate types be known and sufficiently defined so that the instrument control software may be properly coded. Such an approach is difficult, time consuming and inflexible and would require significant software recoding to implement/deploy newly devised plate types. Furthermore, such an approach would more than likely entail recoding the system software as well as recoding the software's representation of a particular plate type.
Therefore, a need exists for flexible software architecture and designs for managing plate data and for supporting field deployable plate types. Such an architecture must be capable of accounting for differences in the plate type configurations (e.g., number and arrangement of wells, sectors and spots; well height and shape; electrode contact configuration; etc.) in addition to different instruments (e.g., ECL-based instruments utilizing specialized plates with different sector, well and spot layouts; fluidics-based instruments; etc.).